Tom kha gai is probably the second best-known Thai dish in America, with pad Thai being the first. Literally translated, tom kha gai means "chicken galangal soup." It's made from chicken lightly poached in a silky coconut milk broth which has been infused with galangal (kha), lemongrass, and makrut or lime leaves. Luckily for those of us who enjoy this Thai soup at restaurants, the hardest part of making tom kha gai at home is simply tracking down the galangal, lemongrass, and limes leaves. And hunting for these few ingredients will be well worth the creamy, savory, spicy, sweet soup that results in their procurement.

Why This Method Is the Best for Home Cooks

Most vibrant chicken soups are built on robust chicken broths, but this version of tom kha gai doesn't require a special broth and opts for chicken thighs instead of chicken breast. Here's why.

A concentrated chicken stock: This soup begins by concentrating chicken broth by reducing it by half. This technique means that any home cook can tackle tom kha gai at home, whether they make homemade chicken stock or buy store-bought broth.

Choose chicken thighs: Chicken thighs replace chicken breast in this version of tom kha gai to prevent overcooked chicken during the poaching process. As the chicken thighs are poached in the concentrated broth and coconut milk, they also lend a bit of fat and extra flavor to the soup, making it richer and creamier.

Addressing Authenticity

Tom kha gai began as a simple dish of braised chicken, coconut milk, and galangal. Much like the other Thai curry-style dishes that we love, tom kha gai is traditionally eaten as an entrée with rice. A bit of cultural confusion may have led to this dish landing in the soup category on restaurant menus and in cookbooks, as tom yum (another Thai dish) is served as a soup.

Recipes for tom kha gai appear in Thai cookbooks as early as 1890 A.D. when the galangal, coconut milk, and a thick chili paste may have been used to offset the pungent aroma of meat in braised dishes. As Thai food intersected with neighboring countries, the dish morphed significantly. Fish sauce was introduced to Thailand by the Chinese, along with rice and chili peppers from the Portuguese.

Thai food wasn't always one of the most popular cuisines in America. In fact, you would have been hard-pressed to find a restaurant it in the United States prior to the 1960s. The first Thai restaurant recorded in the states opened in Denver, Colorado, in 1958 as one of the largest waves of Thai immigrants arrived in the U.S. following the Vietnam war. By 1968, Thai restaurants were a regular fixture in Los Angeles, New York, and London.

Shop Your Soup — Buy the Ingredients for Success

While chicken broth, thighs, coconut milk, and fish sauce can be found at many major markets, the success of tom kha gai depends a few harder-to-find aromatics. Locating galangal, lemongrass, and lime leaves will be the most challenging part of the making this soup, but by seeking out your local Asian market, you should be able to find these essentials with ease.

Galangal

Often associated with ginger, galangal is an aromatic root with a tender peel and woody flesh. It has high spice tones similar to ginger, but also a rich, earthy flavor which ginger cannot replicate. Tom kha gai just isn't tom kha gai without it. Luckily, many Asian markets carry this fragrant rhizome. Look for young galangal, which has a thinner peel than the older stuff and is much easier to eat in the soup.

Lemongrass

Lemongrass is a culinary herb used in everything from soup to curries and even tea. It has a strong lemon aroma that scents every dish it enters. True to its name, lemongrass also has a lemon flavor, but with earthy notes similar to ginger. Often sold in bunches, look for stalks that are clean, fragrant, and free of soft spots. The leaves may be dry, but the stalk should not be. You can freeze chopped lemongrass for future use, so don't shy away from buying a whole bunch even though you'll need only a single stalk for this recipe. You could certainly use lemongrass paste (often found in a tube in the produce department) in a pinch, but it isn't nearly as fragrant as the fresh stuff.

Lime Leaves

Lime leaves are known for their fragrance. They can be hard to locate, but be sure to ask your grocer, as they are sometimes sold frozen. While it's often reported that lime leaves simply cannot be replaced in dishes calling for them, I often substitute lime peel in this soup when I can't find them. When you do find them, stock up and dry or freeze the fresh leaves for future use.

Straw Mushrooms

These mushrooms are native to China and often appear alongside shiitake and oyster mushrooms in soups of this type. Canned versions of this fungi are easily found at most markets, and are worth keeping on hand for adding to other soups, stir-fries, and noodle dishes.

Putting the Work to Work

Unlike other soups in this series, tom kha gai is less of a time commitment as it is a shopping commitment. Buy the galangal, lemongrass, and lime leaves in bulk, and freeze them for making this soup.

The galangal can be used anywhere you might use ginger. Grate it and add to a stir-fry, steep it in tea, or add to warm cider for a sweet punch of flavor.

Lemongrass and lime leaves are also excellent for steeping in other soups, not just tom kha gai. I also love adding lemongrass to homemade pickles, and lime leaves to lentils (especially lentils that will be in cold salads).

Tip: Always make double of this recipe and freeze it. Like many flavorful stews and soups, tom kha gai almost always tastes better the next day, or when you've reheated it from the freezer.

How to Serve and Eat Tom Kha Gai

While this dish would be served with rice on the side in Thailand, it's just as delicious to serve tom kha gai as it is. Just remove the lime leaves and lemongrass before serving. The chiles can also be removed to make a more mild soup.

The Asian Soup Pot

This month, Kitchn is exploring the diverse world of Asian soups. Ramen, pho, and tom kha gai are some of our favorite dishes to eat out, but we tasked ourselves with mastering these soups at home — with equipment we already have and ingredients that are easily found. By pulling in expert advice, shopping smartly, and putting our broth and stock know-how to work, we're bringing these infamous soups from their authentic origins into your home kitchens.

Instructions

Concentrate the broth: Place the chicken broth in a wide and shallow saucepan. Bring the stock to a boil, then boil it over medium-high heat until reduced by half. This step can be done in the soup pot, but will take quite a bit longer.

Infuse the coconut milk: Place the coconut milk, concentrated chicken stock, lime leaves, lemongrass, and galangal in a 4-quart saucepan and bring the mixture to a simmer. Cover and simmer the aromatics to infuse for about 5 minutes.

Cook the chicken and mushrooms: Keeping the mixture at a simmer, add the chicken and mushrooms. Cook uncovered, stirring occasionally, until the chicken is cooked through, about 10 minutes.

Add the seasoning: Add the lime juice, fish sauce, and chiles; stir to combine; and taste. Add a pinch of salt or more lime juice as needed to taste. Remove from the heat, cover, and allow the chiles to infuse for a few minutes.

Garnish and serve: Remove the lime leaves and chiles, if desired, and stir in the cilantro before serving. Serve with lime wedges.

Recipe Notes

Storage: Leftover tom kha gai can be stored in the refrigerator for up to 5 days or frozen for up to 3 months.

Lemongrass: You can substitute lemongrass paste for fresh lemongrass, but reduce the amount to 1 tablespoon.